1. Field of the Invention
The present invention relates to a positional information tracking and forwarding method and system for detecting the current position of a user from the position of a terminal carried by the user in order to forward a call via the user to a telephone installed near the user.
2. Description of the Related Art
Conventionally, customer station exchanges such as a private branch exchange (PBX) for managing telephones within an office, a key system, and the like have a function of automatically forwarding a call to a previously reserved telephone number when a called user is absent. For example, a plurality of telephone numbers may be registered as candidate forward destinations such that a call to the user is forwarded to these telephone numbers in the order in which they were registered, or is forwarded to different forward destinations in different time periods. For example, a call is forwarded to a forward destination in the morning different from a forward destination in the afternoon. Since this forwarding scheme is based on fixed forward rules, it is not the best forward destination control method for estimating the situations of the user.
For example, supposing that a certain person places a telephone call to a mobile worker Mr. A at extension number #A, there is no guarantee that Mr. A will, without fail, respond to the call at this extension number #A. When Mr. A does not-respond at extension number #A, the call to Mr. A is forwarded to registered telephone numbers in the order in which they were registered. Since Mr. A's whereabouts are unknown, the call must be repeatedly forwarded any number of times until Mr. A answers the forwarded call. In the worst case, the call must be forwarded to all registered destinations. Even if the call is forwarded to a different transfer destination on a time period basis, there are no guarantees that Mr. A will be present at the forward destination.
On the other hand, a connection can be ensured if the call is forwarded to a mobile telephone carried by the user. However, simple forwarding to mobile telephones would be mean a high telephone charge. For example, when Mr. A does not respond to a call to him at extension number # A, the call may be forwarded to a mobile phone which he may be carrying. But it is often the case that Mr. A is present in the same company but in a different office in which there is an extension which Mr. A can use free of charge. In another situation, such as when Mr. A is ill and stays at home, for example, a low cost subscriber telephone or a toll-free IP telephone can be used at his house (i.e. instead of the higher cost mole phone). Therefore, despite the availability of such fixed telephone, forwarding a call to Mr. A's mobile phone would result in a higher telephone charge.
To address such an inconvenience, JP-2000-102059-A, JP-4-301955-A, JP-5-130227-A, and JP-7-131535-A, for example, disclose a method which depends on the position of a terminal (for example, a mobile telephone) carried by a user to determine his or her current location, and then forwards the call to the user through telephone (fixed telephone) near the user. This forwarding method is called the “positional information tracking and forwarding method.”
For example, in JP-2000-102059-A, a forwarding center is provided with a forward destination table which stores a plurality of telephone numbers of forward destinations specified by a user which correspond to positional information on the forward destinations. The forwarding center detects the current position of the user from the position of a mobile telephone carried by the user, acquires the telephone number of a forward destination at which the user is highly likely to be present from the forwarding table, and forwards the telephone call to the user at the acquired telephone number.
However, a telephone call acquired from the forward destination table that corresponds to the forward destination where the user is most likely to be, according to the positional information tracking and forwarding method described above, will not be forwarded to other destination if the user is not present at the specific forward destination.
For example, there may be a case where stored forward destinations are in close proximity to one another, such as “Chiyoda Ward,” “Minato Ward,” and “Chuo Ward,” but the forwarding center can only roughly determinate that the user is currently present “near Minato Ward.” In this scenario, the forwarding center acquires a telephone number that corresponds to “Minato Ward” from the forward destination table, as the forward destination at which the user is most likely to be, but the call to the user will only be forwarded to the telephone number that corresponds to “Minato Ward.” Specifically, if the user is not present in “Minato Ward,” the call will not be forwarded to “Chuo Ward” or to “Chiyoda Ward” which are in close proximity to “Minato Ward” even though the user may be present there.
Furthermore, another disadvantage of the system is that once the forwarding center acquires the forward destination table, the call will be forwarded even if the current time is after business hours (at the forward destination), i.e. if the user is not likely to be present.